VBA-M is a fork from the now inactive VisualBoy Advance project, with goals to improve the capatibility and features of the emulator with:
Improved Save Handling
The original vba lacked support for the tiny save files created by games like Kirby's tilt and tumble and Final Fantasy Legends.
Pokemon Gold/Silver/Crystal RTC data is also handled more accurately, resolving the case in 1.7 where you had to reset the clock on every start (A save patcher is available to fix these saves if they were created with 1.7)
Improved Archive Support
ROM images can now be packed with LZMA/LZMA2 7zip, which provides a much better compression ratio for Gameboy(Advance) games.
Improved Input Capabilities
You can now map multiple buttons / devices in the input screen, The bug with certain controls having their AXES wrong in 1.8beta is also resolved.
New built-in Pixel Filters
ASM versions of the HQ3x and 4x, and LQ2-4x filters for better filtering on large screens.
KEGA Fusion Filter Plugin Support
Filters created in this format can also be used if you find one better than the built in filters.
Improves performance when using the heavier filters such as HQ4x.
Fixed Vsync for Direct3D
The Fullscreen menu was removed to resolve a condition where the buffer was unable to lock, resulting in no vsync being applied and causing very noticeable tearing.
ARM Thumb Optimised
Several ARM Thumb optimisation patches from the original project that were never applied to trunk are also implemented, including a fix for the flickering in v-rally that the patch caused.
This improved the sound in many games, and provided the ability to filter out the clicking in some GBC titles. (Anyone with an understanding of the GBA Voice 3 Banks who wants to help resolve some sample issues can contact us)
OpenAL and XAudio support
On Windows Vista and 7, directsound was showing some perceivable audio lag, the OpenAL and Xaudio API's allow us to get lower latency audio on these operating systems.
UPS Patch support
For use with games like Mother3, whose translation patch was provided as a UPS file.
For use with Dolphin-emu, for games like Four Swords Advanced which use the gameboy advance as a controller.
As stated above, anyone with an understanding of the GBA's Channel 3 sample banks can contact us, if they have any idea's for fixing the few sample bugs that have occured.